diff --git a/modules/Gpx/cg.c b/modules/Gpx/cg.c
index 209a55c..ebf98f2 100644
--- a/modules/Gpx/cg.c
+++ b/modules/Gpx/cg.c
@@ -33,7 +33,7 @@
 #include "ags.h"
 #include "pms.h"
 #include "qnt.h"
-#include "sdl_core.h"
+#include "gfx.h"
 #include "ngraph.h"
 #include "dri.h"
 #include "ald_manager.h"
diff --git a/modules/Gpx/graph.c b/modules/Gpx/graph.c
index 3bdcd54..ed44eac 100644
--- a/modules/Gpx/graph.c
+++ b/modules/Gpx/graph.c
@@ -11,7 +11,7 @@
 #include "graph.h"
 #include "ngraph.h"
 #include "ags.h"
-#include "sdl_core.h"
+#include "gfx.h"
 
 /**
  * surface から surface にコピーなどをする際に、転送元と転送先のsurface
diff --git a/modules/NIGHTDLL/nt_scenario.c b/modules/NIGHTDLL/nt_scenario.c
index 3c87e67..e05e87f 100644
--- a/modules/NIGHTDLL/nt_scenario.c
+++ b/modules/NIGHTDLL/nt_scenario.c
@@ -8,7 +8,6 @@
 #include "portab.h"
 #include "system.h"
 #include "input.h"
-#include "sdl_core.h"
 #include "scheduler.h"
 #include "xsystem35.h"
 #include "nact.h"
diff --git a/modules/NIGHTDLL/sprite_eupdate.c b/modules/NIGHTDLL/sprite_eupdate.c
index 7f0a094..7143e7c 100644
--- a/modules/NIGHTDLL/sprite_eupdate.c
+++ b/modules/NIGHTDLL/sprite_eupdate.c
@@ -28,6 +28,7 @@
 #include "ags.h"
 #include "input.h"
 #include "sprite.h"
+#include "gfx.h"
 #include "sdl_core.h"
 
 /*
diff --git a/modules/NightDemonDemo/NightDemonDemo.c b/modules/NightDemonDemo/NightDemonDemo.c
index dbf7732..ed831c5 100644
--- a/modules/NightDemonDemo/NightDemonDemo.c
+++ b/modules/NightDemonDemo/NightDemonDemo.c
@@ -32,6 +32,7 @@
 #include "nact.h"
 #include "alk.h"
 #include "music.h"
+#include "gfx.h"
 #include "sdl_core.h"
 #include "input.h"
 #include "cg.h"
diff --git a/modules/SACT/sactcg.c b/modules/SACT/sactcg.c
index 1106b82..1aa3f05 100644
--- a/modules/SACT/sactcg.c
+++ b/modules/SACT/sactcg.c
@@ -36,7 +36,7 @@
 #include "sact.h"
 #include "sactcg.h"
 #include "cg.h"
-#include "sdl_core.h"
+#include "gfx.h"
 
 #define SPCG_ASSERT_NO(no) \
   if ((no) > (CGMAX -1)) { \
diff --git a/modules/SACT/sprite_eupdate.c b/modules/SACT/sprite_eupdate.c
index 9d2a7b1..22603ad 100644
--- a/modules/SACT/sprite_eupdate.c
+++ b/modules/SACT/sprite_eupdate.c
@@ -29,6 +29,7 @@
 #include "input.h"
 #include "sact.h"
 #include "sprite.h"
+#include "gfx.h"
 #include "sdl_core.h"
 
 /*
diff --git a/modules/tDemo/tDemo.c b/modules/tDemo/tDemo.c
index 040cf6d..c0024d9 100644
--- a/modules/tDemo/tDemo.c
+++ b/modules/tDemo/tDemo.c
@@ -30,6 +30,7 @@
 #include "alk.h"
 #include "input.h"
 #include "bgm.h"
+#include "gfx.h"
 #include "sdl_core.h"
 #include "cg.h"
 #include "jpeg.h"
diff --git a/src/ags.c b/src/ags.c
index 50fae95..80b3579 100644
--- a/src/ags.c
+++ b/src/ags.c
@@ -35,6 +35,7 @@
 #include "xsystem35.h"
 #include "scenario.h"
 #include "ags.h"
+#include "gfx.h"
 #include "sdl_core.h"
 #include "alpha_plane.h"
 #include "utfsjis.h"
diff --git a/src/cmd2F.c b/src/cmd2F.c
index 705f38a..9566737 100644
--- a/src/cmd2F.c
+++ b/src/cmd2F.c
@@ -38,6 +38,7 @@
 #include "utfsjis.h"
 #include "hankaku.h"
 #include "ags.h"
+#include "gfx.h"
 #include "sdl_core.h"
 #include "ald_manager.h"
 #include "LittleEndian.h"
diff --git a/src/cmd_check.c b/src/cmd_check.c
index 61a7bc5..6a7d5ec 100644
--- a/src/cmd_check.c
+++ b/src/cmd_check.c
@@ -32,7 +32,7 @@
 #include "selection.h"
 #include "message.h"
 #include "input.h"
-#include "sdl_core.h"
+#include "gfx.h"
 
 static void undeferr();
 
diff --git a/src/cmdi.c b/src/cmdi.c
index 353dab0..a29632c 100644
--- a/src/cmdi.c
+++ b/src/cmdi.c
@@ -28,7 +28,6 @@
 #include "xsystem35.h"
 #include "scenario.h"
 #include "ags.h"
-#include "sdl_core.h"
 #include "input.h"
 #include "msgskip.h"
 
diff --git a/src/cmdz.c b/src/cmdz.c
index 8dc26bc..9d225a6 100644
--- a/src/cmdz.c
+++ b/src/cmdz.c
@@ -27,6 +27,7 @@
 
 #include "portab.h"
 #include "xsystem35.h"
+#include "gfx.h"
 #include "sdl_core.h"
 #include "scheduler.h"
 #include "ags.h"
diff --git a/src/debugger_dap.c b/src/debugger_dap.c
index e42f283..e6df034 100644
--- a/src/debugger_dap.c
+++ b/src/debugger_dap.c
@@ -31,6 +31,7 @@
 #include "debugger_private.h"
 #include "debug_symbol.h"
 #include "msgqueue.h"
+#include "gfx.h"
 #include "sdl_core.h"
 #include "system.h"
 #include "nact.h"
diff --git a/src/ecopy.c b/src/ecopy.c
index d057358..7c62923 100644
--- a/src/ecopy.c
+++ b/src/ecopy.c
@@ -27,6 +27,7 @@
 #include <math.h>
 
 #include "portab.h"
+#include "gfx.h"
 #include "sdl_core.h"
 #include "input.h"
 #include "ags.h"
diff --git a/src/gfx.h b/src/gfx.h
new file mode 100644
index 0000000..4ccfe13
--- /dev/null
+++ b/src/gfx.h
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2000-     Fumihiko Murata       <fmurata@p1.tcnet.ne.jp>
+ *               2025 kichikuou <KichikuouChrome@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+*/
+#ifndef __GFX_H__
+#define __GFX_H__
+
+#include "config.h"
+#include <SDL_surface.h>
+#include "portab.h"
+#include "ags.h"
+
+/* 初期化関係 */
+int gfx_Initialize(const char *render_driver);
+void gfx_Remove(void);
+
+/* ウィンド関係 */
+void gfx_setWorldSize(int width, int height, int depth);
+void gfx_setWindowSize(int w, int h);
+void gfx_setWindowTitle(char *name);
+void gfx_getWindowInfo(DispInfo *info);
+void gfx_setFullscreen(bool on);
+bool gfx_isFullscreen(void);
+void gfx_raiseWindow(void);
+surface_t *gfx_getDIB(void);
+void gfx_setIntegerScaling(bool enable);
+SDL_Surface *gfx_createSurfaceView(SDL_Surface *sf, int x, int y, int w, int h);
+
+/* 画面更新 */
+void gfx_updateArea(MyRectangle *src, MyPoint *dst);
+void gfx_updateAll(MyRectangle *view_rect);
+void gfx_updateScreen(void);
+
+/* パレット関係 */
+void gfx_setPalette(SDL_Color *pal, int first, int count);
+
+/* 描画関係 */
+void gfx_drawRectangle(int x, int y, int w, int h, uint8_t c);
+void gfx_fillRectangle(int x, int y, int w, int h, uint8_t c);
+void gfx_fillRectangleRGB(int x, int y, int w, int h, uint8_t r, uint8_t g, uint8_t b);
+void gfx_fillCircle(int left, int top, int diameter, uint8_t c);
+void gfx_drawLine(int x1, int y1, int x2, int y2, uint8_t c);
+SDL_Rect gfx_floodFill(int x, int y, int col);
+SDL_Rect gfx_drawString(int x, int y, const char *str_utf8, uint8_t col);
+void gfx_copyArea(int sx,int sy, int w, int h, int dx, int dy);
+void gfx_copyAreaSP(int sx, int sy, int w, int h, int dx, int dy, uint8_t sp);
+void gfx_wrapColor(int sx, int sy, int w, int h, uint8_t cl, int rate);
+void gfx_scaledCopyArea(int sx, int sy, int sw, int sh, int dx, int dy, int dw, int dh, int mirror);
+void gfx_drawImage8(cgdata *cg, int x, int y, int sprite_color);
+void gfx_drawImage16(cgdata *cg, surface_t *sf, int x, int y, int brightness, bool alpha_blend);
+void gfx_drawImage24(cgdata *cg, surface_t *sf, int x, int y, int brightness);
+void gfx_drawImageAlphaMap(cgdata *cg, surface_t *sf, int x, int y);
+void gfx_copyAreaSP16_shadow(int sx, int sy, int w, int h, int dx, int dy, int lv);
+void gfx_copyAreaSP16_alphaBlend(int sx, int sy, int w, int h, int dx, int dy, int lv);
+void gfx_copyAreaSP16_alphaLevel(int sx, int sy, int w, int h, int dx, int dy, int lv);
+void gfx_copy_from_alpha(int sx, int sy, int w, int h, int dx, int dy, ALPHA_DIB_COPY_TYPE flag);
+void gfx_copy_to_alpha(int sx, int sy, int w, int h, int dx, int dy, ALPHA_DIB_COPY_TYPE flag);
+void gfx_getPixel(int x, int y, Palette *cell);
+void gfx_putRegion(void *src, int x, int y);
+void gfx_restoreRegion(void *src, int x, int y);
+void* gfx_saveRegion(int x, int y, int w, int h);
+void gfx_delRegion(void *src);
+void gfx_FlipSurfaceHorizontal(SDL_Surface *s);
+void gfx_FlipSurfaceVertical(SDL_Surface *s);
+
+#endif /* __GFX_H__ */
diff --git a/src/gfx_draw.c b/src/gfx_draw.c
index 2edeb66..8d36fba 100644
--- a/src/gfx_draw.c
+++ b/src/gfx_draw.c
@@ -34,8 +34,9 @@
 
 #include "portab.h"
 #include "system.h"
-#include "sdl_core.h"
+#include "gfx.h"
 #include "gfx_private.h"
+#include "sdl_core.h"
 #include "scheduler.h"
 #include "font.h"
 #include "ags.h"
diff --git a/src/gfx_image.c b/src/gfx_image.c
index 2c74cd5..ec0fd41 100644
--- a/src/gfx_image.c
+++ b/src/gfx_image.c
@@ -28,7 +28,7 @@
 
 #include "portab.h"
 #include "system.h"
-#include "sdl_core.h"
+#include "gfx.h"
 #include "gfx_private.h"
 #include "cg.h"
 #include "nact.h"
diff --git a/src/gfx_video.c b/src/gfx_video.c
index 89974d7..e92ae17 100644
--- a/src/gfx_video.c
+++ b/src/gfx_video.c
@@ -31,8 +31,9 @@
 
 #include "portab.h"
 #include "system.h"
-#include "sdl_core.h"
+#include "gfx.h"
 #include "gfx_private.h"
+#include "sdl_core.h"
 #include "xsystem35.h"
 #include "image.h"
 
diff --git a/src/image.c b/src/image.c
index 090aa1f..0bee8ee 100644
--- a/src/image.c
+++ b/src/image.c
@@ -29,7 +29,6 @@
 #include "cg.h"
 #include "config.h"
 #include "nact.h"
-#include "sdl_core.h"
 #include "alpha_plane.h"
 #include "ags.h"
 
diff --git a/src/nact.c b/src/nact.c
index 0dfc43e..512405c 100644
--- a/src/nact.c
+++ b/src/nact.c
@@ -31,7 +31,7 @@
 #include "portab.h"
 #include "scenario.h"
 #include "xsystem35.h"
-#include "sdl_core.h"
+#include "gfx.h"
 #include "scheduler.h"
 #include "ags.h"
 #include "nact.h"
diff --git a/src/sdl_core.h b/src/sdl_core.h
index 65d2e21..33e0b54 100644
--- a/src/sdl_core.h
+++ b/src/sdl_core.h
@@ -34,59 +34,6 @@
 
 struct inputstring_param;
 
-/* 初期化関係 */
-extern int gfx_Initialize(const char *render_driver);
-extern void gfx_Remove(void);
-
-/* ウィンド関係 */
-extern void gfx_setWorldSize(int width, int height, int depth);
-extern void gfx_setWindowSize(int w, int h);
-extern void gfx_setWindowTitle(char *name);
-extern void gfx_getWindowInfo(DispInfo *info);
-extern void gfx_setFullscreen(bool on);
-extern bool gfx_isFullscreen(void);
-extern void gfx_raiseWindow(void);
-extern surface_t *gfx_getDIB(void);
-extern void gfx_setIntegerScaling(bool enable);
-extern SDL_Surface *gfx_createSurfaceView(SDL_Surface *sf, int x, int y, int w, int h);
-
-/* 画面更新 */
-extern void gfx_updateArea(MyRectangle *src, MyPoint *dst);
-extern void gfx_updateAll(MyRectangle *view_rect);
-extern void gfx_updateScreen(void);
-
-/* パレット関係 */
-extern void gfx_setPalette(SDL_Color *pal, int first, int count);
-
-/* 描画関係 */
-extern void gfx_drawRectangle(int x, int y, int w, int h, uint8_t c);
-extern void gfx_fillRectangle(int x, int y, int w, int h, uint8_t c);
-extern void gfx_fillRectangleRGB(int x, int y, int w, int h, uint8_t r, uint8_t g, uint8_t b);
-extern void gfx_fillCircle(int left, int top, int diameter, uint8_t c);
-extern void gfx_drawLine(int x1, int y1, int x2, int y2, uint8_t c);
-extern SDL_Rect gfx_floodFill(int x, int y, int col);
-extern SDL_Rect gfx_drawString(int x, int y, const char *str_utf8, uint8_t col);
-extern void gfx_copyArea(int sx,int sy, int w, int h, int dx, int dy);
-extern void gfx_copyAreaSP(int sx, int sy, int w, int h, int dx, int dy, uint8_t sp);
-extern void gfx_wrapColor(int sx, int sy, int w, int h, uint8_t cl, int rate);
-extern void gfx_scaledCopyArea(int sx, int sy, int sw, int sh, int dx, int dy, int dw, int dh, int mirror);
-extern void gfx_drawImage8(cgdata *cg, int x, int y, int sprite_color);
-extern void gfx_drawImage16(cgdata *cg, surface_t *sf, int x, int y, int brightness, bool alpha_blend);
-extern void gfx_drawImage24(cgdata *cg, surface_t *sf, int x, int y, int brightness);
-extern void gfx_drawImageAlphaMap(cgdata *cg, surface_t *sf, int x, int y);
-extern void gfx_copyAreaSP16_shadow(int sx, int sy, int w, int h, int dx, int dy, int lv);
-extern void gfx_copyAreaSP16_alphaBlend(int sx, int sy, int w, int h, int dx, int dy, int lv);
-extern void gfx_copyAreaSP16_alphaLevel(int sx, int sy, int w, int h, int dx, int dy, int lv);
-extern void gfx_copy_from_alpha(int sx, int sy, int w, int h, int dx, int dy, ALPHA_DIB_COPY_TYPE flag);
-extern void gfx_copy_to_alpha(int sx, int sy, int w, int h, int dx, int dy, ALPHA_DIB_COPY_TYPE flag);
-extern void gfx_getPixel(int x, int y, Palette *cell);
-extern void gfx_putRegion(void *src, int x, int y);
-extern void gfx_restoreRegion(void *src, int x, int y);
-extern void* gfx_saveRegion(int x, int y, int w, int h);
-extern void gfx_delRegion(void *src);
-void gfx_FlipSurfaceHorizontal(SDL_Surface *s);
-void gfx_FlipSurfaceVertical(SDL_Surface *s);
-
 /* Effects */
 struct sdl_effect;
 struct sdl_effect *sdl_effect_init(SDL_Rect *rect, surface_t *old, int ox, int oy, surface_t *new, int nx, int ny, enum sdl_effect_type effect);
diff --git a/src/sdl_effect.c b/src/sdl_effect.c
index 81aba8c..0cdfbda 100644
--- a/src/sdl_effect.c
+++ b/src/sdl_effect.c
@@ -24,6 +24,7 @@
 #include <SDL.h>
 
 #include "system.h"
+#include "gfx.h"
 #include "sdl_core.h"
 #include "gfx_private.h"
 
diff --git a/src/sdl_event.c b/src/sdl_event.c
index 7f4edf7..36d44c5 100644
--- a/src/sdl_event.c
+++ b/src/sdl_event.c
@@ -35,6 +35,7 @@
 #include "system.h"
 #include "debugger.h"
 #include "nact.h"
+#include "gfx.h"
 #include "sdl_core.h"
 #include "gfx_private.h"
 #include "scheduler.h"
diff --git a/src/sdl_input.c b/src/sdl_input.c
index 3456ba3..ac9f469 100644
--- a/src/sdl_input.c
+++ b/src/sdl_input.c
@@ -22,6 +22,7 @@
 #include <SDL.h>
 
 #include "sdl_core.h"
+#include "gfx.h"
 #include "gfx_private.h"
 #include "menu.h"
 #include "nact.h"
diff --git a/src/win/menubar.c b/src/win/menubar.c
index e2517f7..9fa8b5e 100644
--- a/src/win/menubar.c
+++ b/src/win/menubar.c
@@ -25,6 +25,7 @@
 #include "menu.h"
 #include "nact.h"
 #include "sdl_core.h"
+#include "gfx.h"
 #include "gfx_private.h"
 #include "resources.h"
 #include "msgskip.h"
diff --git a/src/xsystem35.c b/src/xsystem35.c
index 7c00a43..4e895ad 100644
--- a/src/xsystem35.c
+++ b/src/xsystem35.c
@@ -60,6 +60,7 @@
 #include "randMT.h"
 #include "ags.h"
 #include "font.h"
+#include "gfx.h"
 #include "sdl_core.h"
 #include "menu.h"
 #include "music.h"